1. Field of the Invention
This invention relates to an electric motor; and relates in particular to technology enabling supply of variable voltage to the magnetic coils.
2. Description of the Related Art
The brushless motor disclosed in Patent Citation 1 is one example of motors known in the art utilizing permanent magnets and magnetic coils.    Patent Citation 1: JP 2001-298982A
Control of a brushless motor involves using a driver circuit composed of several switching transistors, and applying voltage to the magnetic coils through on/off control of the switching transistors.
Depending on the application for which a motor is used, there are instances in which different voltage values will be used as the supply voltage supplied to the motor. One problem encountered in the past was that in the case of different supply voltages, it was necessary for the drive control circuit of the motor to employ circuits customized for that particular voltage. Accordingly, there existed a need for motor control technology capable of adapting flexibly to changes in supply voltage.